Photocatalytic degradation of ibuprofen on S-doped BiOBr

Doping heterogeneous atoms into BiOX is recognized as an effective method to improve its photocatalytic activity. Here, S-doped BiOBr (S–BiOBr) was synthesized via a solvothermal method in the absence of water, which is supposed to substitute O as S2− in the lattice. This material is firstly used for the visible-light-driven degradation of ibuprofen, a model anti-inflammatory drug. The degradation efficiency of S–BiOBr is much higher than that of pure BiOBr. The degradation kinetic constant for S–BiOBr (2.48 × 10−2 min−1) is about 3 times as high as that of pure BiOBr (0.83 × 10−2 min−1). It is found that S-doping tunes the band structure of BiOBr, leading to a narrower band gap and thus higher utilization efficiency of visible light. The degradation of ibuprofen on S–BiOBr can be attributed to the generation of H2O2 and OH radicals. OH radical plays a synergistic role along with holes in the photocatalytic degradation process, which is supposed to be better than the reported single hole- or superoxide-dominant reaction. This work reveals a previously unrecognized and more efficient method for the degradation of organic contaminants on BiOBr.